Method and apparatus for stripping well pipes



April 20, 1965 G. D. JOHNSON ETAL 3,179,175

METHOD AND APPARATUS FOR STRIPPING WELL PIPES Filed March 29, 1963 3 Sheets-Sheet l 24 FIG. u '7 FIG. I2

INVENTORS.

G. D. JOHNSON J. H. MC CARTHY THEIR AGENT April 1955 G. D. JOHNSON ETAL 3,179,175

METHOD AND APPARATUS FOR STRIPPING WELL PIPES Filed March 29, 1963 3 Sheets-Sheet 2 EE-iii INVENTORSI G. D. JOHNSON J. H. MC CARTHY BY! HIWQW THEIR AGENT April 20, 1955 G. D. JOHNSON ETAL 3,179,175

METHOD AND APPARATUS FOR STRIPPING WELL PIPES Filed March 29, 1965 3 Sheets-Sheet 3 N m m N w m F .00 N. EG V W o O 6 0 %4%4 5 3 M. i uk /7 if J. H MC CARTHY BY: 9

THEIR AGENT United States Patent METHOD AND APPARATUS FOR STRIPPWG WELL PRES Glenn Donnell Johnson, Downey, and John H. McCarthy,

Orinda, Calif., assignors to Shell Oil Company, New

York, N.Y., a corporation of Delaware Filed Mar. 29, 1963, Ser. No. 268,903 14 Claims. .(Cl. 166-46) This invention relates to a method and apparatus for running pipe in and out of a well and pertains more particularly to a method of inserting into or removing from a well a string of pipe which surrounds a second string of pipe of a smaller diameter or a well tool which must be held in tension in the well to prevent it from dropping to the bottom of the well. The operation of inserting a pipe into a well or removing it therefrom, when the pipe surrounds a second pipe or an elongated object already disposed within the well, is commonly referred to as stripping.

In an attempt to locate new oil fields an increasing amount of well drilling has been conducted at offshore locations, such, for example, as off the coast of Louisiana, Texas, and California. As a general rule, the strings of casing in a well, together with the tubing string or strings, extend to a point well above the surface of the water where they are closed in the conventional manner that is used on land Wells, with a conventional Wellhead assembly being attached to the top of the casing. Attempts have been made recently to provide methods and apparatus for drilling, completing and working-over a well wherein both the well casinghead and the various well components secured thereto or suspended therefrom are located underwater at a depth sufficient to allow ships to pass over them. Preferably, the casinghead and its associated equipment are located close to the ocean floor. In order to install equipment of this type underwater in depths greater than the shallow depth at which a diver can easily operate, it has been necessary to design entirely new equipment for this purpose.

In one such method of drilling offshore wells wherein a wellhead base structure is positioned on the ocean floor, strings of pipe, made up of many sections of pipe fastened together, are stripped in and out of the well by the method and apparatus of the present invention.

It is the primary object of the present invention to provide a method and apparatus, the apparatus being simple in design and easy to operate, whereby a larger internal-diameter pipe may be stripped into a well over a smaller diameter pipe or a well tool of smaller diameter.

A further object of the present invention is to provide apparatus for stripping pipe into an offshore well from a platform positioned above the ocean surface, while maintaining tension on an inner pipe string of smaller diameter over which the larger-diameter pipe string is being stripped. Another object of the present invention is to provide simple and safe apparatus adapted to bev connected toand locked on an inner string of pipe to be held in tension while an outer string of pipe is stripped over it.

Still another object of the present invention is to pro vide a method and apparatus for stripping pipe into or out of a well wherein a single hoisting cable is employed.

These and other objects of this invention will be understood from the following description taken with refer ence, to the drawing, wherein:

FIGURE 1 is a longitudinal diagrammatic view illus-' trating cutaway sections of a derrick together with the hoist systems mounted in the. derrick in accordance with the present invention; 1

- FIGURES 2 through 7. are schematic views illustrating "ice the stepwise operations of carrying out the method of the 1 pipe 30.

present invention;

FIGURE 8 is a longitudinal view taken in partial cross section of one form of a connector base to which a connector element may be secured;

FIGURE 9 is a cross-sectional view taken along the line 9-4) of FIGURE 8. FIGURE 10 is an isometric view of the connector base illustrated in FIGURE 8;

FIGURE 11 is an isometric view illustrating the connector element engageable with the connector base of FIGURE 8; and

FIGURE 12 is a longitudinal view taken partly in cross-section of an alternate form of a connector element of FIGURE 11.

Referring to FIGURE 1 of the drawing, numerals 11 and 12 represent fragments of a well derrick, such for example as the type used in drilling wells, which would extend down to an operational base or floor 13, which may be the floor of a derrick or a floor of a drilling platform, either stationary or floatable, as used in drilling offshore wells. The derrick 1112 is provided with a conventional hoist system including a crown block 14, a traveling block 15 provided with a hook 15a and fall lines 16 running to a hoist 16a. Secured to the lower end of the traveling block 15 are elevator links 17 which suspend a conventional pipe-engaging elevator 18. The pipe connector or elevator 18 is designed to clamp around the upper end of a larger internal-diameter pipe string 20, or a section thereof, for raising or lowering the pipe string. In the event that the present hoist system is mounted on a floating drilling barge adapted to move up and down with relation to a wellhead positioned on the ocean floor, the hoist may be a constant tension hoist.

Positioned substantially axially within the larger-diameter outer pipe string 20a is a smaller-diameter inner elongated member such as a cable or pipe string 30 having a support and connector base 31 secured to the top thereof which is adapted to be locked to the connector element 28. The pipe string 20a is illustrated as extending through a hole 32 in the floor 13 of the derrick, and through a spider or rotary table 33 in which slips 34 are wedged in orderto hang the pipe string 20a therefrom.

A hoist or suspending line or cable 24, having a loop 24:: at the top thereof to fit over the hook 15a and be suspended thereby, is provided at the lower end with a connector element 28. The length of the suspending cable 24 is sufficient so that the connector element 28 would be at least slightly below the lower end of a section of pipe 20 when the latter is hanging in the elevators.

In FIGURES 8, 9 and 10, one form of a support and connector base 31 comprises a short cylindrical body member 35 on which are formed a plurality of downwardly and inwardly tapered slip supporting faces 36, 37 and 38 on which slips 4t}, 41 and 42 are mounted for a limited sliding movement in a vertical plane. The adjacent faces of the slips and the slip supporting faces are preferably dove-tailed, as at 43 in FIGURE 9, to prevent the slips from falling away from the body member and to permit actuation of the slip.

As shown in FIGURE 10, the lower ends of the slips 40, 41 and 42 are provided with a T-shaped element 44 on the lower ends thereof that are adapted to slide in radially-extending T-shaped slots 45 formed in the upper. surface of a slip ring 46 which in turn is slidingly mount ed on the body member 35 for limited vertical movement. The lower end of the body member .35 is threaded-- ly connected to a nipple or sub 47. The top of the nipple.

47 forms a shoulder 48. The lower end of the nipple 47 is connectedin any suitable manner, as by threads 50, to the upper end of the inner elongated member which may be a cable but in this instance is a smaller-diameter 'of the slips engage the inner surface of the larger-diameter pipe string or pipe section 20a.

The slip ring 46 is rigidly connected by means of tie rods 53, 54 and 55 to a release collar 56. The release collar 56 is slidingly mounted on a reduced-diameter prtion 57 of the upper end of the body member 35. At the bottom of the reduced-diameter portion 57 of the body member 35 a shoulder 58 is formed. A slip release nut or sleeve 60 threadedly engages the upper end of the reduceddiameter portion 57, as by threads 61.

Suitable connector means are provided at the upper end of the reduced-diameter portion 57 of the body member 35. These may take the form of an upwardly-extending connector arm 62 having a support pin 63 fixedly secured thereto and extending through the arm 62. Bar lugs 64, 65 and 66 are provided on the upper end of the release nut60 to facilitate its rotation. The slip ring 46 is preferably provided with a plurality of resilient or resiliently-mounted drag blocks 67 for slidingly engaging the inner-surface of a surrounding pipe string.

As shown in FIGURES 8, 9 and the slips 40, 41 and 42 are arranged in longitudinal dove-tail grooves which retain the slips in sliding engagement with slip supporting surfaces 36, 37 and 38 of the body member 35, as the slips are moved by axial movement of the slip ring 46 on the body member 35. The slips 40, 41 and 42 are caused to be moved outwardly into their pipe-engaging position through the action of the tapered slip supporting faces when the slip ring 46 is moved toward its upper limit. Conversely, when the slip ring 46 is moved downward with respect to the body member 35, the slips 40, 41 and 42 are caused to move inwardly to their non-operative position where they do not engage the inner surface of a surrounding pipe string.

The compression spring 51 tends to move the slip ring 46 upwardly at all times to force the slips 40, 41 and 42 outwardly into pipe-engaging position. In order to prevent this action, the slip release nut 60 is provided. When the slip release nut 60 is rotated to the right it moves downwardly to engage the release collar 56 causing the latter to move downwardly. Since the slip ring 46 is rigidly secured to the release collar 56 through tie rods 53, 54 and 55, a downward movement of the release collar 56 causes a similar movement to the slip ring 46 which compresses the spring 51 as it moves downwardly and pulls the slips 4t 41 and 42 down along the slip supporting faces 36, 37 and 38 to their known inoperative position.

Left-hand rotation of the slip release nut 60 causes it to be threaded upwardly on the reduced-diameter portion 57 of the body member 35 thus allowing the release collar 56, slip ring 46 and slips 40, 41 and 42 to move upward as they are acted on by compression spring 51. It is to be noted that the slip release nut 63 is elongated sufliciently so that its upper end to which a wrench may be threaded'box end. The slip supporting faces 36, 37 and 38 maybe provided with pins 68 for limiting the upward movement of the slips 40, 41 and 42.

The connector element 28 of FIGURE 1 is illustrated 1 in FIGURES. 11 and 12 as being provided with an upwardly-extending slot 70 which is slightly wider than the connector arm 62 of the connector base 31. Additionally, the connector element .28 is provided with a pin 'slot 71 which enters. the body of the connector 28 laterally, makes a generally right angle and then extends 4 downwardly parallel to the axis of the connector 28. The support pin 63 extending through the connector arm 62 of the top of the support and connector base 31 is of a size to pass readily through the pin slot 71 and seat at the lower end thereof. It is tobe understood that the pin slot 71 is formed in the opposite walls of the connector 28 that form the upwardly extending slot 70. The lower end of the connector 28 may be curved, as at 72, in order to facilitate engagement of the support pin 63 in the pin slot 71 of the connector 25. The hoist cable 24 is secured to the top of the connector 28 in any manner Well known to the art.

In performing an operation in accordance with the present invention of stripping a larger internal diameter pipe into a well over a smaller diameter pipe or other inner elongated member such as a cable, the operation would start as illustrated in FIGURE 1 with the pipe 20a of larger internal diameter being held by means of slips 34 in a fixed position within the spider or rotary table 33. At the same time the support and connector base 31 would have been secured to the top of the smaller diameter inner elongated member or pipe string 30 and be supported by the slips 4t 41 and 42 which engage the inner wall of the outer pipe string 20a of larger diameter as the slip release nut 60 has been threaded upward to its slip-release position. Thus, both the outer pipe string 20a and the inner pipe string 34 are held in tension as they extend from the operating platform 13 into a well therebelow.

Cable 16 is run off the hoist drum 16a so that the hook 15a carried by the traveling block 15 is lowered sufi'lciently so that the elevatorslS can be connected to the upper end of a section of pipe 20 of larger internal diameter to be added to the upper end of the pipe string Ztla of the same diameter being suspended from the slips 34 in the rotary table 33. The connector element 28 at the lower end of the suspending line 24 is run down through the pipe single or section 20 in a manner illustrated in FIGURE 1.

The traveling block 15 and hook 15a together with elevators 18, pipe section 21B and suspending line 24 are raised so that they are suspended directly above the pipe string 20a held in the rotary table 33. The connector 28 is then manually turned to a substantially horizontal position (FIGURE 2) so that the pin slot 71 (FIGURES 11 and 12) in the connector 28 can engage the pin 63 on the top of the support and connector base 31 in a manner shown in FIGURE 12.

With the connector 23 secured to the connector base 31, traveling block 15 israised by means of hoist drum 16a sulficiently to pick up the connector base 31 and the guide pipe or inner pipe string 30 until the weight of the connector base 31 and pipe. string 3% has been transferred from the slips 40, 41 and 42 to the suspending cable 24. With the support and connector base slips 4t), 41 and 42 in a non-operative position, the slip release nut 60 is threaded downwardly against release collar 56 (FIGURE 10) to hold the slips 40, 41 and 42 in a retracted position (FIGURE 3). The connector 28 and the connector base 31 togetherwith the cable 24 and inner guide pipe string 30 are lowered down into the outer pipe string of larger diameter 219a until the lower end of the new pipe section 20, supported by the elevators 18, is in engagement with the upper end of the pipe, string 20a and is threadedly secured thereto (FIGURE 4). The traveling block 15 and all of the elements supported thereby are then raised slightly so that the slips 34 (FIGURE 4) can be disengaged from the outer pipe string 20a thus allowmg the larger'diameter outer pipe string to be lowered down through the rotary table until the upper endof the newly-connected pipe section 20 (FIGURE 5) is just above the rotary table 33.

At this point slips 34 are again inserted in the rotary table 33 to suspend the pipe section '21) and the elevators 18 are disconnected from the upper end of the pipe section. The traveling block 15, elevators 18 and suspending cable 24 are then raised a distance suflicient to allow slip release nut 60 of the support and connector base 31 to emerge from the top of the pipe section 20 (FIGURE 6). The exposed slip release nut 60 is threaded up on threads 61 (FIGURE 1) as by a wrench 74 (FIGURE 6) in an operation which is the reverse of that shown in FIGURE 3. This allows the slips 40, 41 and 42 to move outwardly in pipe-engaging contact with the inner wall of the outer pipe string 20 or 20a (FIGURE 8). The traveling block 15 would then be lowered slightly to allow the slips 40, 41 and 42 to support the inner pipe string 30 within the pipe section 20. With the inner elongated member or pipe string 30 again supported from a point near the top of the larger diameter pipe tension would be relaxed on the suspension cable 24 allowing the connector 28 at the lower end of the cable 24 to be removed from the support and connector base 31 (FIGURE 7). By repeating the cycle of operations described, the desired amount of larger diameter pipe can be stripped into a well over a smaller diameter pipe or cable.

In an alternative method of stripping pipe 20 into a well while using the apparatus of the present invention, the steps of the method as described with regard to FIGURES l and 2 are first carried out. However, with regard to FIG- URES 3 and 4, the slip release nut .60 need not be screwed down or used in any manner whatsoever as it is not essential that the slips 40, 41 and 42 be held in their retracted position when stripping pipe into a well. Thus, after securing the connector 28 to the connector base 31, as shown in FIGURE 3, the pipe section 20 could be lowered into engagement with the upper end of the largerdiameter pipe string 20a when the slips 40, 41 and 42 on the connector base were still in engagement with the inner smaller-diameter pipe string in tension. The elevators would then lower both pipe strings through the rotary table 33 (FIGURE 5) and, after setting holding slips 34 in place, the elevators 18 would be disconnected and hook 15a raised. This would cause the suspending line 24 to pull the connector base 31 above the open upper end of the larger diameter outer pipe. The drag blocks 67 on the slip ring 46 (FIGURE during this withdrawal operation would bear against the inner surface of pipe 20 and provide suflicient friction to hold the slip ring 46 and slips 40, 41 and 42 in a downward or inoperative position as the support and connector base 31 is pulled up through the pipe 20.

To remove a larger internal diameter pipe from a well and strip it up off a small diameter pipe or cable, the above-described procedure including use of the slip release nut 60 would be reversed. After the suspending cable 24 and its connector 28 were positioned above the rotary table, the connector (FIGURE 7) would be se cured to the upper end of the support and connector base 31 so that the weight of the inner pipe string or cable 30 could be transferred from the slips of the connector base 31 to the suspending line 24. The traveling block would be pulled upwardly slightly to permit theslips 40, 41 and 42 to be released from weight-supporting contact with pipe 20 and allow slip release nut 60 to be screwed down to hold the slips in retracted position (FIGURE 6). The traveling block 15, elevators 18 and suspending line 24 Would then all be lowered until the elevators 18 could engage the upper end of the larger internal diameter pipe section 20. The traveling block elevator 18 would be raised so that the pipe string and the suspending cable 24 were raised simultaneously a distance sufficient so that the entire length of the pipe section 20 was above the rotary table 33.

At this point the slips 34 would be again inserted in the rotary table 33 to suspend the larger-diameter outer pipe string while the upper section 20 thereof was unscrewed (FIGURE 4), after which, the traveling block 15 and hook 1511 together with elevators 18 and pipe section 26) is raised enough so that the connector base 31 emerges from the top of the pipe string 20a permitting slip release unit 60 to be threaded upward to release the slips 40, 41 and 42. The traveling block would be lowered slightly to allow the weight of the inner elongated member or pipe string 30 and its support and connector head 31 to be transferred from the suspending line 24 to the slips 40, 41 and 42. With tension released on the suspending cable 24, the connector 28 would be disconnected from the support and connector head 31 and moved to one side so that the traveling block 15 and hook 156: could be lowered to lay down pipe section 20 after which the elevators 18 would be disconnected and the suspending line 24 and its connector 28 pulled out of the pipe section 20. The cycle of operations could then be repeated to strip other sections of pipe out of the well. i i

We claim as our invention:

1. A method of stripping a larger internal-diameter outer pipe string over a smaller-diameter inner elongated member which is axially movable, said method comprising the sequential steps of (a) suspending temporarily said larger internal diameter outer pipe string and anchoring and supporting said inner member within and in engagement with said larger-internal diameter outer pipe string by a first suspending element,

(11) running a second suspending element through a section of larger internal-diameter outer pipe to be added to the top of said outer pipe string,

(c) jointly suspending and moving said pipe section to be added and said second suspending element carried therein into substantial longitudinal position above said suspended outer pipe string,

(d) connecting said second suspending element to said inner. member,

(e) transferring the weight of said inner member from said first suspending element to said second suspending element to disengage said inner member from supported engagement with said outer pipe string,

(7) lowering said larger internal-diameter pipe section into engagement with said outer pipe string while maintaining said inner member in tension within said outer pipe string, and i (g) connecting the pipe section to the outer pipe string.

2. The method of claim 1 wherein said first suspending elementand said inner elongated member are lowered together within said outer pipe string while said larger internal-diameter pipe section is lowered into engagement with said outer pipe string.

3. The method of claim 1 wherein the weight of said inner member is transferred to said second suspending element by applying tension to said secondsuspending element. i

4. The method of claim 1 including the steps of subsequently lowering said outer pipe string and said inner member simultaneously a distance substantially equal to the pipe section added, andanchoring the outer pipe string independent of said inner member against further downward movement.

5. The method of claim4. including the subsequent step of raising the inner member until the upper end of said first suspending element emerges from the top of the outer pipe string.

6. A method of stripping a larger internal-diameter pipe string down over a smaller-diameter pipe string having at least the lower end thereof positioned within a well, said method comprising the sequential steps of (a) fixedly suspending said larger internal-diameter outer pipe string by engaging the outer surface thereof,

(b) attaching a support and connector base to the top of the inner pipe string,

(c) supporting said inner pipe string from the inner surface of said larger internal-diameter pipe string near the top thereof,

(d) running a suspending cable through a section of larger internal-diameter outer pipe to be addedto the top of said outer pipe string,

(e) jointly suspending and moving said outer pipe section with said suspending cable positioned substantially concentrically therein into substantial longitudinal position above said suspended outer pipe string,

(1) connecting the lower end of said suspending cable to said support and connector base,

(g) raising said pipe section and said suspending cable simultaneously to suspend the inner pipe string from said cable,

(h) arranging said inner pipe string and said support andconnector base in an axially movable manner within said outer pipe string,

(i) lowering the larger internal-diameter pipe section into engagement with said suspended outer pipe string and connecting the pipe section to said outer pipe string,

(j) simultaneously lowering said inner and outer pipe strings'a distance substantially equal to the pipe sec tion added, and

(k) again suspending said outer larger-internal diameter pipe string independent of, said smaller diameter inner pipe string.

7. The method of claim 6 including the subsequent step of raising the inner pipe string in suspension until the top of the support and connector base thereof is above the top of the outer pipe string.

8. A' method of stripping a larger internal-diameter outer pipe string up over a smaller-diameter axially-movable inner elongated member, said method comprising the sequential steps of (a) fixedly suspending said outer pipe string from the outer surface thereof,

(b) connecting a first suspending element to said inner elongated member to suspend said inner member therefrom,

(a) lowering said first suspending element and said smaller-diameter inner elongated member into said larger internal-diameter outer pipe string a distance substantially equal to the length of a pipe section of said outer pipe string,

(d) engaging said larger internal-diameter outer pipe string above its suspension point with a second suspending element and simultaneously raising said inner elongated member and said outer pipe string until at least one section of the outer pipe string is above its previously suspended position,

(e) again fixedly suspending said outer pipe string at a point below the uppermost pipe section thereof,

(1) disconnecting at least one pipe section from the top of said outer pipe string,

(g) raising said disconnected pipe section until at least the top of the inner member is exposed,

(h) supporting said inner elongated member by engagement with the inner surface of the outer pipe string near the top thereof, and

(i) disconnecting said first suspending element from said inner smaller diameter elongated member.

O Q 9. Apparatus for use in Well operations for selectively stripping to or from a well a larger internal-diameter pipe string over a smaller-diameter inner elongated member held in tension throughout the operation, said apparatus comprising (a) an operational and support base positioned adjacent said pipe string,

(b) hoist means including hoist vcable means having a portion arranged for vertical movement above said pipe to be stripped out of the well,

(0) connector means secured to said hoist cable means,

said connector means including (d) a first connector of a size adapted to connect to V the upper end of said larger internal-diameter outer pipe string,

(e) a second connector connected to said inner elongated member and being of a diameter to pass through said outer pipe string and being of a length sufiicient to extend beyond said first connector a distance greater than the length of a section of pipe in said outer pipe string,

(1) slip-type hanger means adapted to be carried by the upper end of said smaller-diameter inner elongated member and adapted to engage the inner surface of said larger internal-diameter outer pipe string to support said inner elongated member in said ,outer pipe string, and

g) slip-type anchoring means for engaging the larger internal-diameter outer pipe string to'selectively and temporarily secure it relative to said base against axial movement.

10. The apparatus of claim 9 wherein said first connector comprises a traveling block and a pipe-engaging elevator secured thereto.

11. The apparatus of claim 10 wherein said second connector includes a flexible cable secured to said traveling block of said hoist means and arranged to depend therefrom in concentric arrangement within said elevator and having means at the lower end thereof for engaging the upper end of said inner elongated member.

12. The apparatus of claim 9 wherein said hanger means includes a plurality of slips mounted on tapered slip supporting surfaces and actuating means operatively connected to said slips for normally urging them outwardly to an operative position.

13. The apparatus of claim 12 wherein said slip-actuating means includes spring means operatively engaging said slips for urging them along the slip surfaces.

14. The apparatus of claim 13 including slip retaining means operatively engagable with said slips in one position to hold said slips in a retracted position.

References (Jilted by the Examiner UNITED STATES PATENTS 2,758,654 8/56 Simmons 166-49 X 2,782,004 2/57 l-larrigan 166-46 X 2,998,067 8/61 Kerver 16646 3,100,015 8/63 Regan 166-46 CHARLES E. OCONNELL, Primary Examiner. 

1. A METHOD OF STRIPPING A LARGER INTERNAL-DIAMETER OUTER PIPE STRING OVER A SMALLER-DIMETER INNER ELONGATED MEMBER WHICH IS AXIALLY MOVABLE, SAID METHOD COMPRISING THE SEQUENTIAL STEPS OF (A) SUSPENDING TEMPORARILY SAID LARGER INTERNAL DIAMETER OUTER PIPE STRING AND ANCHORING AND SUPPORTING SAID INNER MEMBER WITHIN AND IN ENGAGEMENT WITH SAID LARGER-INTERNAL DIAMETER OUTER PIPE STRING BY A FIRST SUSPENDING ELEMENT, (B) RUNNING A SECOND SUSPENDING ELEMENT THROUGH A SECTION OF LARGER INTERNAL-DIAMETER OUTER PIPE TO BE ADDED TO THE TOP OF SAID OUTER PIPE STRING, (C) JOINTLY SUSPENDING AND MOVING SAID PIPE SECTION TO BE ADDED AND SAID SECOND SUSPENDING ELEMENT CARRIED THEREIN INTO SUBSTANIAL LONGITUDINAL POSITION ABOVE SAID SUSPENDED OUTER PIPE STRING, (D) CONNECTING SAID SECOND SUSPENDING ELEMENT TO SAID INNER MEMBER, (E) TRANSFERRING THE WEIGHT OF SAID INNER MEMBER FROM SAID FIRST SUSPENDING ELEMENT TO SAID SECOND SUSPENDING ELEMENT TO DISENGAGE SAID INNER MEMBER FROM SUPPORTED ENGAGEMENT WITH SAID OUTER PIPE STRING, (F) LOWERING SAID LARGER INTERNAL-DIAMETER PIPE SECTION INTO ENGAGEMENT WITH SAID OUTER PIPE STRING WHILE MAINTAINING SAID INNER MEMBER IN TENSION WITHIN SAID OUTER PIPE STRING, AND (G) CONNECTING THE PIPE SECTION TO THE OUTER PIPE STRING. 